<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .loading{width: 300px;height: 50px;margin: 30px auto;}
        .loading div{width: 50px;height: 50px;background: blueviolet;border-radius: 25px;float: left;
        animation: name 2s infinite linear;}

        @keyframes name{
            0%{transform:scale(0.5);}
            50%{transform: scale(1.5);}
            100%{transform: scale(0.5);}
        }
        .loading div:nth-child(1){animation-delay: -0s;}
        .loading div:nth-child(2){animation-delay: -0.25s;}
        .loading div:nth-child(3){animation-delay: -0.5s;}
        .loading div:nth-child(4){animation-delay: -0.75s;}
        .loading div:nth-child(5){animation-delay: -1s;}
    </style>
</head>
<body>
    <div class="loading">
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
    </div>
</body>
</html>